
Jacklyn S. answered 04/02/25
Doctor Available to Tutor High School/College/Med Students
Virtually all parts of the human body are colonized by bacteria -and without them, we'd be in trouble! For example, we have a variety of bacteria in the gut that do many things for us such as helping digest food and producing chemicals needed to process the food. They also produce vitamin K, which is essential for us to be able to form clots when we're bleeding. Multiple studies have shown that the makeup of our gut microbiome correlates with various disease states including depression, anxiety, chronic pain, and diabetes.
In and of itself, having bacteria somewhere doesn't mean there's an infection. Our skin is colonized by many bacterial species, most notably Staphylococcus and Streptococcus species. They just live on us and likely protect us from more pathogenic bacteria colonizing and then invading. However, when we do develop a skin infection such as cellulitis or folliculitis, the most common causative organisms are Staph and Strep, because they already live on the surface of our skin. They cause infection when they invade too deeply into the skin.